Proximity and tap detection using a wireless system

ABSTRACT

A method for detecting the proximity of a signal source using wireless systems is contemplated in which a wireless mobile device wirelessly receives packets from a signal source and determines a received signal strength for each packet. The wireless mobile device may store information based upon the received signal strength for each packet, and calculate from the information stored for all the packets, a current path loss value corresponding to a current distance from the wireless mobile device to the signal source. The wireless mobile device may then determine whether the current distance is sufficient to be an enabling condition such as tap, for example, for a data transfer or a transaction between the wireless mobile device and the signal source.

PRIORITY CLAIM

This application is a continuation of U.S. patent application Ser. No.13/760,452, filed Feb. 6, 2013, which claims priority to U.S.Provisional Patent Application Ser. No. 61/696,058, filed Aug. 31, 2012,which are herein incorporated by reference in their entirety.

BACKGROUND

1. Technical Field

This disclosure relates to wireless communication devices, and moreparticularly to a wireless mobile device detecting proximity to anotherwireless device using wireless signals.

2. Description of the Related Art

The use of wireless communication systems has rapidly evolved frompredominantly voice-only communications to the transmission of data,such as Internet and multimedia content.

Recently, there has been a trend for wireless devices to be able totransfer data to, or to conduct a transaction with another device suchas a wireless mobile device or a stationary wireless device byphysically bumping or tapping the wireless mobile device into the seconddevice. This bump or tap may be sensed by, for example, sensors in oneor both devices. The devices may then transfer data or conduct atransaction between them.

However, it may not be desirable to have to physically tap or bump thewireless mobile device into the other device to initiate the datatransfer, or the transaction.

SUMMARY OF THE EMBODIMENTS

Various embodiments of a method for detecting the proximity of a signalsource using wireless systems are disclosed. Broadly speaking, a methodis contemplated in which a wireless mobile device wirelessly receivespackets from a signal source and determines a received signal strengthfor each packet. The wireless mobile device may store information basedupon the received signal strength for each packet, and calculate fromthe information stored for all the packets, a current path loss valuecorresponding to a current distance from the wireless mobile device tothe signal source. The wireless mobile device may then determine whetherthe current distance is sufficient to be an enabling condition such astap, for example, for a data transfer or a transaction between thewireless mobile device and the signal source.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of one embodiment of a wireless communicationsystem.

FIG. 2 is a diagram of one embodiment of proximity zones between asignal source and a wireless mobile device.

FIG. 3 is a block diagram of one embodiment of a wireless mobile deviceshown in FIG. 1.

FIG. 4 is a flow diagram depicting the operation of one embodiment ofthe wireless mobile device shown in FIG. 3.

Specific embodiments are shown by way of example in the drawings andwill herein be described in detail. It should be understood, however,that the drawings and detailed description are not intended to limit theclaims to the particular embodiments disclosed, even where only a singleembodiment is described with respect to a particular feature. On thecontrary, the intention is to cover all modifications, equivalents andalternatives that would be apparent to a person skilled in the arthaving the benefit of this disclosure. Examples of features provided inthe disclosure are intended to be illustrative rather than restrictiveunless stated otherwise.

As used throughout this application, the word “may” is used in apermissive sense (i.e., meaning having the potential to), rather thanthe mandatory sense (i.e., meaning must). Similarly, the words“include,” “including,” and “includes” mean including, but not limitedto.

Various units, circuits, or other components may be described as“configured to” perform a task or tasks. In such contexts, “configuredto” is a broad recitation of structure generally meaning “havingcircuitry that” performs the task or tasks during operation. As such,the unit/circuit/component can be configured to perform the task evenwhen the unit/circuit/component is not currently on. In general, thecircuitry that forms the structure corresponding to “configured to” mayinclude hardware circuits. Similarly, various units/circuits/componentsmay be described as performing a task or tasks, for convenience in thedescription. Such descriptions should be interpreted as including thephrase “configured to.” Reciting a unit/circuit/component that isconfigured to perform one or more tasks is expressly intended not toinvoke 35 U.S.C. §112, paragraph six, interpretation for thatunit/circuit/component.

The scope of the present disclosure includes any feature or combinationof features disclosed herein (either explicitly or implicitly), or anygeneralization thereof, whether or not it mitigates any or all of theproblems addressed herein. Accordingly, new claims may be formulatedduring prosecution of this application (or an application claimingpriority thereto) to any such combination of features. In particular,with reference to the appended claims, features from dependent claimsmay be combined with those of the independent claims and features fromrespective independent claims may be combined in any appropriate mannerand not merely in the specific combinations enumerated in the appendedclaims.

DETAILED DESCRIPTION

As mentioned above, some wireless mobile devices may have the capabilityto physically tap or bump another wireless mobile device or a stationarywireless device to initiate (i.e., tap event) an exchange of data suchas a monetary transaction or data transfer, for example. In somescenarios these devices typically include accelerometers or othersensors that detect the bump, and can then initiate a security orhandshake between the devices. In other scenarios, a wireless mobiledevice may send out a signal and when the wireless mobile device isclose enough to a passive non-powered device, the electromagnetic fieldcreated by the wireless mobile device signal may power up thenon-powered device through magnetic coupling. These types of proximitytaps are typically restricted to a few centimeters. As described in thefollowing embodiments of FIG. 1 through FIG. 4, various embodiments aredisclosed in which a wireless mobile device may be able to determine itsdistance from another device that is emitting a particular signal,whether stationary or mobile, and to determine whether that distance isclose enough to enable a data transfer or some other type of transactionwith the other device (i.e., to be considered a tap event).

Turning now to FIG. 1, a block diagram of one embodiment of a wirelesscommunication system is shown. It is noted that the system of FIG. 1 ismerely one example of any of a variety of wireless communicationsystems. The wireless communication system 10 includes a base station102 which communicates over a wireless transmission medium (as indicatedby the zig-zag) with one or more user equipment (UE) devices (e.g., 106Athrough 106N). The base station 102 is also coupled a network 100 viaanother interface, which may be wired or wireless. Each of the UEdevices 106A through 106N are also coupled to each other UE device 106Athrough 106N via a wireless transmission medium. Lastly, as shown, UEdevice 106B is coupled via the wireless transmission medium to awireless access point 104. It is noted that components identified byreference designators that include both a number and a letter may bereferred to by the number only where appropriate.

The base station 102 may be a base transceiver station (BTS) or cellsite, and may include hardware that enables wireless communication withone or more of the UEs 106. The base station 102 may also be equipped tocommunicate with the network 100. Thus, the base station 102 mayfacilitate communication between the UEs 106 and/or between the UEs 106and the network 100. The communication area (or coverage area) of thebase station 102 may be referred to as a “cell.” In various embodiments,the base station 102, the UEs 106, and the wireless access point 104 maybe configured to communicate over the transmission medium using any ofvarious wireless communication radio access technologies such as LTE,GSM, CDMA, WLL, WAN, WiFi, WiMAX, Bluetooth, Bluetooth LE, and othersfor example.

In one embodiment, each of the UEs 106A-106N may be representative of awireless mobile device with wireless network connectivity such as amobile phone, a hand-held device, a computer or a tablet, or virtuallyany type of wireless device. As described further below, the UE 106 mayinclude at least one processor (shown in FIG. 3) that is configured toexecute program instructions stored in a memory (also shown in FIG. 3).Accordingly, in some embodiments, the UE 106 may perform one or moreportions of the functionality described below by executing such storedinstructions. However, in other embodiments, the UE 106 may include oneor more hardware elements and/or one or more programmable hardwareelements such as an FPGA (field-programmable gate array) that may beconfigured to perform the one or more portions the functionalitydescribed below. In still other embodiments, any combination of hardwareand software may be implemented to perform the functionality describedbelow.

In one embodiment, the wireless access point 104 may be representativeof a stationary or mobile point of sale terminal that is wirelesslytransmitting packets at some predetermined interval. For example, a cashregister at a retail business may include a wireless transceiver forconducting wireless transactions. In another embodiment, the wirelessaccess point 104 may be representative of a stationary or mobile accesspoint such as a wireless router, for example, that is wirelesslytransmitting packets at some predetermined interval and which providesaccess to a computer network, and or the Internet. In various otherembodiments, the wireless access point 104 may generally provide accessbetween the UE 106 and any of a variety of computer and/or cellularnetwork functions.

As described further below in conjunction with the descriptions of FIG.2 through FIG. 4, in some embodiments, the UE 106 may be configured towirelessly receive packets from a signal source such as another UE 106,or the wireless access point 104, for example. The UE 106 may alsodetermine the distance to the signal source, and determine whether thatdistance is sufficient to enable an exchange of data with the signalsource (i.e., the device transmitting the packets).

Turning to FIG. 2, a diagram of illustrating one embodiment of proximityzones between a user equipment device and another wireless device isshown. As shown, UE 106A is some distance away from the wireless accesspoint 104 and the UE 106B. As indicated by the circles, the distancefrom the wireless access point 104 and the UE 106B is delineated intozones. More particularly, zone 0 corresponds to a first radius, zone 1corresponds to a second radius, zone 2 corresponds to a third radius,and zones n and m correspond to respective fourth radii, where n and mmay be any whole number, and where zone 0 is closer than zone n or m. Asthe UE 106A gets closer to the wireless access point 104, the UE 106Aenters zone n of the wireless access point 104 and if the UE 106Acontinues to move closer, it will transition from zone n to zone 2 tozone 1, and finally to zone 0. In a similar way, as the UE 106A movescloser to UE 106B it will enter zone m and transition to zones 2, 1, and0.

In one embodiment, each zone may correspond to a different distance foreach device. For example, depending on the type of device and particularapplication, a given device may have zones that correspond to one set ofdistances, and another device may have zones that correspond to adifferent set of distances. In addition, as mentioned above eachwireless access point 104 may provide a different service.

In various embodiments, the wireless access point 104 may broadcastpackets at a predetermined interval. In one particular embodiment, thewireless access point 104 and the UE 106B may broadcast the packetsusing the Bluetooth LE protocol. As such, the packets may be encoded asadvertising packets. The advertising packets may include the address ofthe transmitting device, information corresponding to connectivitycapability, a universal unique identifier (UUID) that identifies thedevice as “tappable,” and the transmit power at which the packet wastransmitted, among others. However, it is contemplated in otherembodiments the packets may be broadcast with a different encoding, andthey may be broadcast using any type of wireless communication standard.In various embodiments, the wireless access point 104 may act as aserver, and the UE 106A may act as a client in a client-serverarrangement.

In one embodiment, when the UE 106A begins receiving these advertisingpackets, UE 106A may begin determining the distance to the wirelessaccess point 104 based upon the received signal strength indication(RSSI) of the packets. In addition, the UE 106A may determine whetherthe distance is sufficient to enable a transaction or data transferbetween the UE 106A and the wireless access point 104. In oneembodiment, once the determination is made, application software runningon the UE 106A may determine whether to automatically and without userintervention begin the transaction or transfer, or whether userintervention may be needed.

In another embodiment, the UE 106B may act as a server. Moreparticularly, in such an embodiment, the UE 106B may broadcast packetsin a way similar to the wireless access point 104. However, the packetbroadcast may, in one embodiment, not be continuous, but rather whenprompted by particular application software, or when activated by userinteraction with a software application. In either case, if the UE 106Bbegins broadcasting the advertising packets, when the UE 106A beginsreceiving these advertising packets, UE 106A may begin determining thedistance to the UE 106B based upon the received signal strength (RSSI)of the packets. In addition, the UE 106A may determine whether thedistance is sufficient to enable a transaction or data transfer betweenthe UE 106A and the UE 106B.

As described in greater detail below in conjunction with thedescriptions of FIG. 3 and FIG. 4, in various embodiments, the UE 106Amay include a proximity unit that may include hardware, software, or acombination that may be used by one or more applications running on theUE 106A to determine the distance to a signal source, and to determinebased upon some predetermined parameters whether the distancecorresponds to an enabling condition (i.e., a tap event) for an exchangeof data between the UE 106A and the UE 106B.

Referring to FIG. 3, a block diagram of one embodiment of a userequipment device of FIG. 1 is shown. It is noted that components thatcorrespond to components shown in FIG. 1 are numbered identically forclarity and simplicity. The UE 106 includes processor(s) 202 (orprocessor core(s) 202) which is coupled to display circuitry 204 whichis in turn coupled to the display 240. The processor(s) 202 is alsocoupled to a memory management unit (MMU) 220, which is coupled to amemory 206. The processor(s) 202 is also coupled to areceiver/transmitter (R/T) unit 230, and to a proximity detection unit260. The UE 106 also includes an I/O interface 210 that is coupled tothe processor(s) 202, and may be used for coupling the UE 106 to acomputer system, or other external device. It is noted that in oneembodiment the components shown within UE 106 of FIG. 2 may bemanufactured as stand alone components. However, it is contemplated thatin other embodiments various ones of the components may be part of oneor more chipsets, or they may be part of a system on chip (SOC)implementation.

In various embodiments, the processors 202 may be representative of anumber of different types of processors that may be found in a wirelesscommunications device. For example, processor(s) 202 may include generalprocessing capability, digital signal processing capability, as well ashardware accelerator functionality, as desired. The processor(s) 202 mayinclude baseband processing and therefore may digitally process thesignals received by the R/T unit 230. The processor(s) 202 may alsoprocess data that may be transmitted by the R/T unit 230. Theprocessor(s) 202 may also perform a number of other data processingfunction such as running operating system and user applications for theUE 106.

In one embodiment, the MMU 220 may be configured to receive addressesfrom the processor(s) 202 and to translate those addresses to locationsin memory (e.g., memory 206) and/or to other circuits or devices, suchas the display circuitry 204, R/T unit 230, and/or display 240. The MMU220 may also return data to the processor(s) 202 from the locations inmemory 206. The MMU 220 may be configured to perform memory protectionand page table translation or set up. In some embodiments, the MMU 220may be included as a portion of the processor(s) 202. The displaycircuit 204 may be configured to perform graphics processing and providedisplay signals to the display 240.

The R/T unit 230 may, in one embodiment, include analog radio frequency(RF) circuitry for receiving and transmitting RF signals via the antenna235 to perform the wireless communication. The R/T unit 230 may alsoinclude down-conversion circuitry to lower the incoming RF signals tothe baseband or intermediate frequency (IF) as desired. For example, theR/T unit 230 may include various RF and IF filters, local oscillators,mixers, and the like. Since the UE 106 may operate according to a numberof radio access technologies, the R/T unit 230 may include acorresponding number of RF front end portions to receive anddown-convert, as well as up-convert and transmit the respective RFsignals of each technology. For example, in one specific implementation,the R/T unit 230 may include an LTE front end and an IS-2000 front end.

In various embodiments, the processor(s) 202 may execute software storedwithin a memory such as memory 206 and memory 266, for example, toperform functionality associated with determining the distance to asignal source, and determining whether the distance corresponds to a tapevent as mentioned above, and described further below. Accordingly,memory 206 and memory 266 may be representative of any type ofnon-transitory computer readable storage medium or device such as anydevice in the random access memory (RAM) family of devices, for example.Additionally, the software instructions may be stored on aportable/removable storage media and transferred to memory 206 and/ormemory 266. In other embodiments however, the UE 106 may includehardware associated with the processor(s) 202 and/or the R/T 230 toperform functionality associated with determining the distance to asignal source, and determining whether the distance corresponds to a tapevent as mentioned above. In still other embodiments, the UE 106 mayinclude any suitable combination of hardware, firmware and /or softwareto perform functionality associated with the tune-away mode as mentionedabove, and described further below in conjunction with the descriptionof FIG. 4.

In one embodiment, the proximity unit 260 may be configured to storepackets received from a signal source such as a wireless access point104 or another UE 106. The proximity unit 260 may use the RSSI values tocalculate a current path loss value from a number of RSSI values. In oneembodiment, the proximity unit 260 may calculate a path loss value froman average of a number of RSSI values. The path loss value may becalculated as the difference between the transmitted power of thepackets and the received power of the packets as measured by theproximity unit 260. The path loss value corresponds to the distance fromthe UE 106 to the signal source because generally the greater thedistance, the greater the path loss will be. Thus, in one embodiment,lower path loss values correspond to shorter distances. As mentionedabove, in one embodiment, the packet may include a value correspondingto the transmitted power of the packet. In another embodiment, thetransmitted power of the packet may already be known, based upon thetype of device broadcasting the packets. In such cases, the device typemay be included in the packets.

The proximity unit 260 may store enough packets to reliably calculatestable RSSI values and corresponding path loss values. However, becauseRSSI measurements and calculations can be less reliable as distance fromthe signal source increases, the proximity unit 260 may be configured togather (sample) more packets the farther away the UE 106 is from thesignal source (and thus the higher the zone), and to sample fewerpackets as the UE 106 gets closer to the signal source. In oneembodiment, more samples may be gathered when the UE 106 is in higherzones because, as described further below, there may be many outliervalues, and many of the high and low RSSI outlier values may bediscarded. This active filtering occurs dynamically and automaticallyduring operation. Accordingly, the proximity unit 260 may initialize asbeing in the farthest zone, and thus sample and store a larger number ofpackets, and then compare to values associated with lower zones. Eachzone may correspond to a maximum and a minimum path loss value, therebycreating a path loss value range. If the current path loss value fallsoutside the range for a given zone, the proximity unit 260 compares thecurrent path loss value to the range of the next adjacent zone. Thiscontinues until the current path loss value either falls within therange of a particular zone or the current path loss value falls belowthe minimum value of the lowest (i.e., closest zone). The selection ofthe next adjacent zone is determined by whether the current path lossvalue is higher than the maximum value or lower than the minimum value.

In one embodiment, the proximity unit 260 may receive information froman application executing on processor 202. More particularly, in oneembodiment, the determination of whether a particular distancecorresponds to a tap event may be dependent on the type of applicationthat is running For example, a user may not want to initiate a paymentterminal transaction 25 feet away from the terminal, but may allow apayment transaction from two feet. Thus, the application software mayprovide specific parameters such as the tap event distance, or thecorresponding zone to the proximity unit 260, to allow the proximityunit 260 to make the determination. However, in other embodiments, theproximity unit 260 may provide the current distance and/or thecorresponding zone to the application software to enable the applicationsoftware to make the final tap even determination.

In addition, in one embodiment, to prevent an inadvertent second tapevent once a tap event has been detected, the proximity unit 260 may beconfigured to determine whether the zone has increased from the zonethat UE 106 was in when the last tap event was detected. Otherwise theproximity unit 260 may not re-arm for another tap event. In other words,in one embodiment, to detect a subsequent tap event the proximity unit260 must detect that the UE 106 moved away from the signal source farenough to be in the next higher zone, before moving back into the zonein which tap event would be detected.

It is noted that in one embodiment, the UE 106 may be configured tocontinuously monitor for the advertising packets and thereby act as aclient device. However, in other embodiments, the UE 106 may beconfigured to monitor for the advertising packets in response toinstructions from application software executing on processor(s) 202.

It is further noted that the UE 106 may also operate as the serverdevice, as described above in reference to the operation of UE 106B inthe description of FIG. 2. Accordingly, the UE 106 may be configured tosend packets such as the advertising packets, for example. In oneembodiment, the UE 106 may begin sending the packets in response toexecution of particular application software executing on theprocessor(s) 202. Alternatively, the UE 106 may begin sending thepackets in response to another type of trigger.

In FIG. 4, a flow diagram depicting the operation of one embodiment ofthe wireless user equipment device of FIG. 1 through FIG. 3 is shown.Referring collectively to FIG. 1 through FIG. 4 and beginning in block401 of FIG. 4, the UE 106 may be receiving packets from a signal sourcesuch as a wireless access point (e.g., 104) or another wireless devicesuch as another UE. The proximity unit 260 may store the incomingpackets in a storage such as memory 266, or memory 206, as desired(block 403). As described above, the number of packets may correspond tothe zone within which the UE determines that it is currently within.Upon first receiving the packets, the proximity unit 260 may start inthe farthest zone.

The proximity unit 260 may calculate RSSI values from the packets in thestorage (block 405). From the RSSI values and the transmitted powervalues of the stored packets, the proximity unit 260 may calculate acurrent path loss value, which may be the difference between thereceived signal strength and the transmitted signal strength. Thiscurrent path loss value corresponds to the current distance that the UEis away from the signal source (block 407). In one embodiment, theproximity unit 260 may discard some number of the highest and lowestRSSI values, and average the remaining RSSI values. In one embodimentthe average may be a straight average. In another embodiment, theaverage may be a weighted average, with more weight being given to morerecent values. The number of discarded values may depend upon thecurrent zone, with more values being discarded in farther zones. Moreparticularly, as the distance between the signal source and the UEincreases, there may be more opportunities for multipath artifacts,which may present themselves abnormally weak signals. In addition,abnormally high strength signals for a given zone may also be presentdue, for example, to alternative signal paths. In various embodimentsthe proximity unit 260 may compare the RSSI values to a pair of per-zonethreshold values, one high and one low for each zone. The per-zonethreshold values may be determined using any of a variety of statisticalmethods, for example.

The proximity unit 260 may then compare the current path loss value tothe maximum and minimum values that make up the range for the currentzone. If the current path loss value is not within the range of thecurrent zone (block 409), the proximity unit 260 may check to determineif the current zone is the lowest zone (block 411). If it is not thelowest (i.e., closest zone), the proximity unit 260 starts comparing thecurrent value to the next lower adjacent zone range (block 413). Inaddition, the proximity unit 260 may continue to receive packets andcalculate the current path loss values concurrent with the comparisonwith the various zone ranges. Further, as the UE moves closer to thesignal source from zone to zone, and the proximity unit 260 compares thecurrent path loss values in lower zones, the proximity unit 260 usesfewer packets to calculate the current path loss value (block 415). Ifthe current path loss value is still not in the range of the nextadjacent zone, the proximity unit 260 continues changing to the nextlowest zone (block 413), checking until the current value is eitherbeing compared to the lowest zone (block 411), or the value falls withinthe range of the current zone. Once the current path loss value falls inthe range of the current zone (block 409), the proximity unit 260 maydetermine if the current range corresponds to a tap event (block 417).In one embodiment, the proximity unit 260 may compare the distance thatcorresponds to current zone with one or more predetermined parameterssuch as the distance from the signal source. As mentioned above theparameters may be provided by application software executing on theprocessor(s) 202.

If the proximity unit 260 determines that the current zone does notqualify as a tap event, operation proceeds as described above inconjunction with the description of block 401. However, referring backto block 417, if the proximity unit 260 determines that the current zonedoes qualify as a tap event, the proximity unit 260 may notify theapplication software of the tap event (block 419).

As mentioned above, once a tap event has been detected, the proximityunit 260 may reduce the occurrence of any subsequent inadvertent tapevents. More particularly, in one embodiment, the proximity unit 260will not re-arm proximity detection until it determines that the UE hasmoved away from the signal source by at least one zone (block 421). Ifthe proximity unit 260 detects that the current path loss value fallswithin at least one next higher zone, then operation as described abovein conjunction with the description of block 401.

Although the embodiments above have been described in considerabledetail, numerous variations and modifications will become apparent tothose skilled in the art once the above disclosure is fully appreciated.It is intended that the following claims be interpreted to embrace allsuch variations and modifications.

What is claimed is:
 1. A method comprising: wirelessly receiving, by awireless mobile device, packets from a signal source and determining areceived signal strength corresponding to the received packets;calculating, based at least in part on information corresponding to thedetermined received signal strength, a current path loss valuecorresponding to a current distance from the wireless mobile device tothe signal source; and determining, by the wireless mobile device,whether the current distance is within a threshold distance for a tapevent initiating an exchange of data between the wireless mobile deviceand the signal source, wherein the tap event comprises physicallytapping the wireless mobile device into a field of the signal source. 2.The method as recited in claim 1, wherein the determining whether thecurrent distance is within a threshold distance for a tap eventcomprises comparing the current path loss value to a plurality ofpredetermined path loss ranges to determine within which of the pathloss ranges the current path loss value falls, wherein each path lossrange corresponds to a different distance from the wireless mobiledevice to the signal source.
 3. The method as recited in claim 2,wherein the determining whether the current distance is within athreshold distance for a tap event further comprises comparing the pathloss range within which the current path loss value falls to apredetermined distance parameter.
 4. The method as recited in claim 2,wherein the calculating the current path loss value comprises storinginformation for a predetermined number of packets, wherein thepredetermined number is based at least in part on which range of theplurality of predetermined path loss ranges the current path loss valuefalls within.
 5. The method as recited in claim 4, further comprising,responsive to receiving the packets, comparing the current path lossvalue to a path loss range corresponding to a largest distance from thewireless mobile device to the signal source.
 6. The method as recited inclaim 4, wherein calculating the current path loss value includesdiscarding given ones of the received signal strength values in responseto determining that the given received signal strength value is eitherabove a first signal strength threshold or below a second signalstrength threshold for each range of the plurality of predetermined pathloss ranges.
 7. The method as recited in claim 1, wherein the packetsreceived from the signal source correspond to advertising packets, andthe signal source corresponds to a wireless server unit.
 8. The methodas recited in claim 7, wherein the wireless server unit comprisesanother wireless mobile device.
 9. The method as recited in claim 7,wherein the wireless server unit comprises a point of sale terminal andthe exchange of data corresponds to a transaction.
 10. The method asrecited in claim 7, wherein the wireless server unit comprises awireless access point providing access for the wireless mobile device toa network.
 11. A wireless mobile device comprising: a transceiver unitconfigured to receive packets from a signal source; a processor coupledto the transceiver unit; and a proximity unit coupled to the processorand configured to determine a received signal strength for receivedpacket; wherein the proximity unit is further configured to calculate,using information corresponding to the received signal strength, acurrent path loss value corresponding to a current distance from thewireless mobile device to the signal source; and wherein the proximityunit is further configured to determine whether the current distance iswithin a threshold distance for a tap event initiating an exchange ofdata between the wireless mobile device and the signal source, whereinthe tap event comprises physically tapping the wireless mobile deviceinto a field of the signal source.
 12. The wireless mobile device asrecited in claim 11, wherein the proximity unit is further configured tocompare the current path loss value to a plurality of predetermined pathloss ranges to determine within which of the path loss ranges thecurrent path loss value falls, wherein each path loss range correspondsto a different distance from the wireless mobile device to the signalsource.
 13. The wireless mobile device as recited in claim 12, whereinthe proximity unit is further configured to compare the path loss rangewithin which the current path loss value falls to a predetermineddistance parameter.
 14. The wireless mobile device as recited in claim12, wherein the proximity unit is further configured to storeinformation for a predetermined number of packets, wherein thepredetermined number is based upon which range of the plurality of pathloss ranges the current path loss value falls within.
 15. The wirelessmobile device of claim 14, wherein in response to initially receivingthe packets, the proximity unit is further configured to compare thecurrent path loss value to a path loss range corresponding to a largestdistance from the wireless mobile device to the signal source.
 16. Anon-transitory computer readable storage medium including programinstructions that are executable by a processor of a wireless mobiledevice to: receive packets from a signal source; determine a receivedsignal strength for each packet; calculate, based upon informationcorresponding to the received signal strength for each of the packets, acurrent path loss value corresponding to a current distance from thewireless mobile device to the signal source; and determine whether thecurrent distance comprises a tap event initiating an exchange of databetween the wireless mobile device and the signal source, wherein thetap event comprises physically tapping the wireless mobile device into afield of the signal source.
 17. The non-transitory computer readablestorage medium of claim 16, wherein the program instructions areexecutable by a processor of a wireless mobile device to compare thecurrent path loss value to a plurality of predetermined path loss rangesto determine within which of the path loss ranges the current path lossvalue falls, wherein each path loss range corresponds to a differentdistance from the wireless mobile device to the signal source.
 18. Thenon-transitory computer readable storage medium of claim 17, wherein theprogram instructions are executable by a processor of a wireless mobiledevice to compare the path loss range within which the current path lossvalue falls to a predetermined distance parameter.
 19. Thenon-transitory computer readable storage medium of claim 17, wherein theprogram instructions are executable by a processor of a wireless mobiledevice to store information for a predetermined number of packets,wherein the predetermined number is based upon which range of theplurality of path loss ranges the current path loss value falls within.20. The non-transitory computer readable storage medium of claim 19,wherein the program instructions are executable by a processor of awireless mobile device to store more packets the farther away thewireless mobile device is from the signal source, and to store fewerpackets as the wireless mobile device gets closer to the signal source.